BS4庫簡單使用:
1.最好配合LXML庫，下載：pip install lxml
2.最好配合Requests庫，下載：pip install requests
3.下載bs4：pip install bs4
4.直接輸入pip沒用？解決：環境變數->系統變數->Path->新建：C:Python27Scripts
案例：獲取網站標題
# -*- coding:utf-8 -*-
from bs4 import BeautifulSoup
import requests
url = “https://www.baidu.com”
response = requests.get(url)
soup = BeautifulSoup(response.content, `lxml`)
print soup.title.text
標籤識別
示例1：
# -*- coding:utf-8 -*-
from bs4 import BeautifulSoup
html = “`
<html>
<head><title>The Dormouse`s story</title></head>
<body>
<p class=”title”><b>The Dormouse`s story</b></p>
<p class=”story”>Once upon a time there were three little sisters; and their names were
<a href=”http://example.com/elsie” class=”sister” id=”link1″>Elsie</a>,
<a href=”http://example.com/lacie” class=”sister” id=”link2″>Lacie</a> and
<a href=”http://example.com/tillie” class=”sister” id=”link3″>Tillie</a>;
and they lived at the bottom of a well.</p>
<p class=”story”>…</p>
</body>
</html>
“`
soup = BeautifulSoup(html, `lxml`)
# BeautifulSoup中有內建的方法來實現格式化輸出
print(soup.prettify())
# title標籤內容
print(soup.title.string)
# title標籤的父節點名
print(soup.title.parent.name)
# 標籤名為p的內容
print(soup.p)
# 標籤名為p的class內容
print(soup.p[“class”])
# 標籤名為a的內容
print(soup.a)
# 查詢所有的字元a
print(soup.find_all(`a`))
# 查詢id=`link3`的內容
print(soup.find(id=`link3`))
示例2：
# -*- coding:utf-8 -*-
from bs4 import BeautifulSoup
html = “`
<html>
<head><title>The Dormouse`s story</title></head>
<body>
<p class=”story”>Once upon a time there were three little sisters; and their names were
<a href=”http://example.com/elsie” class=”sister” id=”link1″>Elsie</a>,
<a href=”http://example.com/lacie” class=”sister” id=”link2″>Lacie</a> and
<a href=”http://example.com/tillie” class=”sister” id=”link3″>Tillie</a>;
and they lived at the bottom of a well.</p>
<p class=”story”>…</p>
</body>
</html>
“`
soup = BeautifulSoup(html, `lxml`)
# 將p標籤下的所有子標籤存入到了一個列表中
print (soup.p.contents)
find_all示例:
# -*- coding:utf-8 -*-
from bs4 import BeautifulSoup
html = “`
<div class=”panel”>
<div class=”panel-heading”>
<h4>Hello</h4>
</div>
<div class=”panel-body”>
<ul class=”list” id=”list-1″>
<li class=”element”>Foo</li>
<li class=”element”>Bar</li>
<li class=”element”>Jay</li>
</ul>
<ul class=”list list-small” id=”list-2″>
<li class=”element”>Foo</li>
<li class=”element”>Bar</li>
</ul>
</div>
</div>
“`
soup = BeautifulSoup(html, `lxml`)
# 查詢所有的ul標籤內容
print(soup.find_all(`ul`))
# 針對結果再次find_all,從而獲取所有的li標籤資訊
for ul in soup.find_all(`ul`):
print(ul.find_all(`li`))
# 查詢id為list-1的內容
print(soup.find_all(attrs={`id`: `list-1`}))
# 查詢class為element的內容
print(soup.find_all(attrs={`class`: `element`}))
# 查詢所有的text=`Foo`的文字
print(soup.find_all(text=`Foo`))
CSS選擇器示例：
# -*- coding:utf-8 -*-
from bs4 import BeautifulSoup
html = “`
<div class=”panel”>
<div class=”panel-heading”>
<h4>Hello</h4>
</div>
<div class=”panel-body”>
<ul class=”list” id=”list-1″>
<li class=”element”>Foo</li>
<li class=”element”>Bar</li>
<li class=”element”>Jay</li>
</ul>
<ul class=”list list-small” id=”list-2″>
<li class=”element”>Foo</li>
<li class=”element”>Bar</li>
</ul>
</div>
</div>
“`
soup = BeautifulSoup(html, `lxml`)
# 獲取class名為panel下panel-heading的內容
print(soup.select(`.panel .panel-heading`))
# 獲取class名為ul和li的內容
print(soup.select(`ul li`))
# 獲取class名為element，id為list-2的內容
print(soup.select(`#list-2 .element`))
# 使用get_text()獲取文字內容
for li in soup.select(`li`):
print(li.get_text())
# 獲取屬性的時候可以通過[屬性名]或者attrs[屬性名]
for ul in soup.select(`ul`):
print(ul[`id`])
# print(ul.attrs[`id`])